U.S. patent application Ser. No. 13/538,456, entitled Interleaved Signaling, and U.S. patent application Ser. No. 13/841,313, entitled Orthogonal Signal Demodulation, the disclosures of which are hereby incorporated by reference in their entireties, relate to the transmission, modulation and demodulation of data through the use of various signaling techniques. The signaling described in the incorporated patent applications, as well as other types of wired and wireless signaling, may be susceptible to impairments added to the transmitted signal as it traverses a signal path. Particularly problematic impairments may result from random noise and/or burst noise. Random noise may be continuous in the time domain and generally flat or “white” in the frequency domain. Burst noise may be strong in amplitude, but relatively short in duration, which may include the noise being wide in frequency. Burst noise may be caused by switching in electrical circuits, such as switching regulated power supplies, switching inductive loads with mechanical contacts, automotive ignitions, and power supplies for lighting such as compact florescent lamps, etc.
Forward error correction (FEC), Reed-Solomon (RS) codes, low-density parity-check codes (LDPC) and error other block FEC techniques, such as but not necessarily limited to those described in the incorporated patent applications, may be used to ameliorate channel errors resulting noise related impairments. One non-limiting aspect of the present invention contemplates supplementing and/or replacing such error correction techniques in order to facilitate ameliorating noise influences on transmitted signaling.
Block codes have overhead, in the form of additional data added to allow FEC. Generally a stronger error correction ability requires more overhead. When a noise burst is received, an efficient block code with low overhead, which was designed to correct random symbol errors associated with Gaussian (random) noise, will be unable to correct all of the errors caused by the burst. This results in an uncorrectable block. A solution that has been implemented is interleaving, where the noise burst is spread over multiple code blocks, and each code block receives a lesser number of symbol errors, resulting in a corrected code block.